For some reason the Red Bulls have struggled mightily on July 4; and if they hope to turn that around tomorrow in Colorado (9:30 p.m., MSG) they’ll have to do it at altitude and minus one key midfielder.

Brazilian standout Juninho – who leads the team with four assists – will miss the Rapids game due to a personal matter, according to coach Mike Petke. But striker Fabian Espindola did snap his personal eight-game scoreless drought in Sunday’s 2-0 win over Houston, and striker Thierry Henry has recovered well enough from Corey Ashe’s slide tackle to be expected to play as well.

Yet, there is still the concern of playing at altitude – Denver is officially 5,280 feet above seas level – and on Independence Day, when the Red Bulls are just 1-8-2.

“Altitude is not (that bad). I know it’s a nice storyline; but the altitude’s altitude. Everybody has to deal with it,’’ said Petke, who played in Denver. “Does it change the way we want to play? Not necessarily. Does it change the way we’ll approach the game? Perhaps a little bit. But it’s not something we’re putting into the players’ minds, not something that we’re severely altering what we want to do.’’

Regarding their July 4 woes, Petke said “I don’t know (why that’s the case)…I’ve played in Colorado many times with New York, whether it’s the MetroStars or the Red Bulls. It’s a tough place to play. They always get a sellout crowd on 4th of July, you know it pumps it up, pumps the players up, whatever reason. But we’re looking to change that obviously for Thursday.’’

The MetroStars lost 2-1 in Colorado on July 4 in MLS’ inaugural season, and has played there four times on Independence Day and never won. As a matter of fact, Henry remembers their struggles in his last visit, a 4-1 loss on July 20, 2011.

“I remember going there and being down after 20 minutes or 25 minutes, three-nil if I remember well; so we know exactly how it’s going to be over there and we’ve got to be prepared,’’ Henry said of the Rapids, who just are coming off a 4-3 win at East-leasing Montreal. “It’s not an easy task. So they have done something that no one has done for a little while against Montreal so we have to be aware of that.

“We all know it is difficult to play at their place because of the altitude and because also they’re a good team. So we’re going to have to be ready for that and make sure that we can defend well and see if we can score one.’’